Mysterious message in Rails output at launch

For the last couple of days, the following message has started
up on stdout (not in the .log file) at startup when I run script/
or start mongrel in my development environment, or run a Rails unit
– tables()
-> 0.0210s

Apparently this is telling my about execution time for a method call
somewhere. But I never asked for it.

Where is this message coming from? I don’t recall turning on any
logging, or installing any plugins or new gems. I’ve grepped through
all the code I can find. It’s very mysterious.

Any suggestions on where to look next are greatly appreciated.